A component mounting apparatus that mounts components, like semiconductor devices, on a substrate, repeatedly performs component mounting operation. Specifically, each of mounting heads picks up, by means of vacuum suction, a component from a component feeding unit where a plurality of parts feeders, like tape feeders, are disposed side by side. The mounting head then transfers and populates the component on a substrate positioned and held by a substrate holding unit. Faulty operation; that is, unreliable holding and releasing of a component due to stability of vacuum pickup, is likely to occur during the component mounting operation. For instance, in mounting operation for mounting components on a substrate, a component is released from a pickup nozzle by means of halting vacuum suction. At this time, there may be a case where a component will still remain adhered to and unreleased from a pickup surface of the pickup nozzle for any reasons. In such a case, a so-called “brought-back component” occurs. More specifically, during the component mounting operation, a component has not been mounted on a substrate and returns to the component feeding unit along with the mounting head while remaining unmounted. For this reason, next component mounting operation cannot be performed normally, which causes an operation error.
In order to detect such a brought-back component, a hitherto-employed component mounting apparatus has a component detecting function for detecting whether or not a component still exists on any of lower ends of pickup nozzles of mounting heads; namely, whether or not a component remains adhered to any of the lower ends (see; for instance, Patent Document 1). The related art described in connection with the example patent document is directed toward a configuration in which a component detector made up of a light projector and a line sensor camera is disposed while a transfer pathway along which a corresponding mounting head moves back and forth between a substrate retaining unit and a component feeding unit is taken as an inspection object. When a pickup nozzle of the mounting head crosses a belt-shaped inspection beam projected from the light projector toward the line sensor camera, the line sensor camera captures an image. By means of the image, detection is made as to whether or not a component still exists on any of the pickup nozzles.